I mean, nothing of this is new. ESEA, one of the most influential esports leagues, was caught using its anticheat to mine Bitcoin in 2013. [1] This is long out of control, probably since the days BattlEye switched to ring0 in 2012 due to chronic cheating in the DayZ mod, or maybe earlier. Modern anticheats are full-fledged rootkits with extremely complex and targeted payloads siphoning customer data and hijacking all sorts of stuff, and that's not a theory, they actively abuse players' trust and indifference.
If you care about your data and the control of your devices, you should probably avoid them entirely, or at least use them on dedicated gaming PCs on a clean identity, and keep them separate from your LAN and your non-gaming digital life.